In handling articles, such as cans, of identical size, it is a common practice to stack such articles in layers upon pallets for ease in transporting and in storing the same. The stacking of articles on pallets, that is palletizing, may be effected by hand. However, when large quantities of articles are to be handled, such hand palletizing is very time consuming and costly. For this reason, palletizing systems and machines have been built and used. Such prior art apparatus, however, suffers from one or more deficiencies such as excessive cost, limited application, and versitility, and the like.
In order to stack articles in more than a single layer, it is often desirable to arrange the layers of articles in a predetermined pattern, which pattern is repeated for each layer whereby articles in an upper layer are positioned directly over articles in a lower layer. Prior art methods and means often involve hand labor for effecting such a pattern. Where the pattern forming has been mechanized, the machinery associated therewith is often complicated and limited in its application.
When conveying items from one place to another on a conveyor line, such as an endless belt or the like, it is a common practice to include an accumulator in the line to compensate for differences in the rate at which items are fed to and removed from the ends of the line. The prior art accumulators include large complicated revolving platforms, or the like, which require a great amount of space, are complicated in nature and require frequent maintenance.
The transfer of a layer of oriented articles from the accumulator section to a receiving pallet requires a lifter means for lifting all the articles contained in the accumulator and transferring them simultaneously to the receiving pallets. Many of the prior art devices utilize a vacuum system consisting of a suction cup for each individual article. Such vacuum transfer systems for individual articles were complicated in nature and difficult in their control.
In order to stack articles in more than a single layer it is desirable to place a slip-sheet layer separator between the layers of articles. In many of the prior art palletizers, the slip-sheets were manually placed on the layers of cans as they are stacked. The use of manual labor to position the layer separator slip-sheets defeats the whole purpose of automatic palletizing equipment.
In order to make an article palletizing system completely automatic, it is necessary to provide a pallet storage magazine for successively feeding pallets to the palletizing stations as they are required. Nurerous attempts have been made to construct pallet magazines with means for dispensing pallets individually as they are required by the pallet receiving station. Most of the prior art devices for dispensing pallets were complicated in nature and unreliable in their operation.